LEDs (Light Emitting Diodes) have come into widespread use in backlights for display devices and lighting equipment as light sources that conserve more energy than light bulbs and fluorescent lights, in accordance with improved efficiency in recent years. Many light-emission devices using light-emission elements such as LEDs have conventionally been proposed. A light-emission device where a light-emission element mounted on a substrate is covered with a resin containing a phosphor (fluorescent particles) is particularly well known. There is demand in recent years for further improvement in light-emission efficiency. A double-sealed light-emission device, having a structure where phosphor-containing resin that covers a light-emission element mounted on a substrate is further sealed by a transparent resin, has been proposed to improve light-emission efficiency.
For example, PTL 1 describes a light-emission device including a first LED set and a second LED set disposed within a reflecting cup, a first set of phosphor layers coating the first LED set, and a second set of phosphor layers coating the second LED set, where a transparent layer is configured covering these sets, and further, a diffusion layer that can be combined with the transparent layer is disposed above the transparent layer (hereinafter referred to as “first light-emission device”).
PTL 1 also describes a light-emission device having surface-adhering LEDs, to which the above-described light-emission device has been applied (hereinafter referred to as “second light-emission device”). More specifically, this second light-emission device is configured with a first LED set and second LED set adhered onto a base, and a transparent layer is configured covering the first LED set and second LED set. A first set of phosphor layers and a second set of phosphor layers are configured to respectively cover the first LED set and second LED set, at positions of the transparent layer corresponding to the first LED set and second LED set. Further, a transparent enclosure layer is disposed so as to cover the first LED set, second LED set, transparent layer, first set of phosphor layers, second set of phosphor layers, and an input terminal.